Weird Boot Error: virbr0 starting userspace STP failed
I suddenly could not boot my Linux box (Fedora 11) today. It showed some error messages as follows,
virbr0: starting userspace STP failed, starting kernel STP ADDRCONF(NETDEV_UP): eth0: link is not ready e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: None 0000:00:19.0: eth0: 10/100 speed: disabling TSO ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
In the beginning, I thought it is related to network or libvirtd. But I did not solve the problem by turning off libvirtd. I did not change anything in my last boot. But I updated Fedora packages using Software Update. However, I did not pay attention what I updated. By searching on web, I found some people talked about this issue after upgrading video drivers. I felt it may be the same reason.
My video card is Nvidia. I used nvidia linux driver (NVIDIA-Linux-x86-190.42-pkg1.run) downloaded from nvidia web site. To give it a try, I decided to reinstall it. So I boot at runlevel 3, and run the driver installer NVIDIA-Linux-x86-190.42-pkg1.run again in text mode. It rebuilt the driver and reset xorg.conf. Then, the problem was fixed.
After that, I found that there are actually a lot of errors in /var/log/Xorg.?.log such as
NVIDIA: Failed to load the NVIDIA kernel module. Please check your system's kernel log for additional error messages.
Also, /var/log/messages log has error message as follows.
WARNING: GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors init:prefdm main process terminated with status 1
So this weird boot error is really caused by video driver. The errors related to virbr0 were just coincident errors that showed up after X failed to start. I checked my logs. Such errors have been there for every boot. I just did not see them. Now I turn off libvirtd service.
FYI, to boot into runlevel 3 in this hanging case. Select the linux image entry to boot in GRUB, press ‘e’. In next screen, move to the kernel line, press ‘e’. In my case, it ends up with ‘rhgb quiet’, which is redhat graphic boot. Delete ‘rhgb, quite’, replace it with ‘3′. Then press ‘b’. It will boot to runlevel 3 without starting those daemons or X window. Just log in as root and reinstall the video driver. If runlevel 3 does not work, try single user mode, i.e. replace ‘rhgb quite’ with ’single’.
Ruby MySQL adapter on Windows
It is very easy to install Ruby MySQL adapter using gem on Windows.
gem install mysql
But I found Ruby MySQL adapter does not work with MySQL 5.1 on my Windows box. When Ruby executed SQLs or Rails server got requests, I got some errors like this
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/ connection_adapters/abstract_adapter.rb:39: [BUG] Segmentation fault ruby 1.8.6 (2009-08-04) [i386-mingw32] This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.
It seems the reason is that this version of mysql gem does not work with MySQL 5.1 lib. I saw some suggestions on Web to downgrade MySQL to 5.0 to solve the problem. However, I don’t want to downgrade MySQL. It turns out the solution is very simple. Download MySQL 5.0 noinstall version mysql-noinstall-5.0.89-win32.zip from http://dev.mysql.com/downloads/mysql/5.0.html. Extract libmysql.dll and copy it to C:\Ruby\bin. Then, the problem is solved. I am still running MySQL 5.1. But Ruby uses this MySQL 5.0 version dll.
My environment: Ruby 1.8.6. Gem 1.3.5. MySQL gem version 2.8.1. Rails version is 2.3.5. Windows XP and MySQL 5.1.
Install MySQL for Python (MySQLdb) on Windows
It took me quite a while to figure out how to build and install MySQL for Python (MySQLdb) on Windows. I’d better write it down.
There is no binary distribution of MySQLdb for Python 2.6 on Windows. I have to build it from the source. My environment is Windows XP. MySQL 5.1. Python 2.6 (windows version, not cygwin), and MySQL-python-1.2.3c1. Also, I have Microsoft Visual C++ 2008 Express Edition (Microsoft Visual Studio 9.0) installed, which is required to compile the C code in MySQL-python.
First of all, install Python setuptools, if you haven’t installed it. It is required in MySQL-python setup.py. I also added C:\Python26\Scripts into environment PATH, where easy_install is installed.
Then, make sure you have MySQL Developer Components installed. Download MySQL msi installer version, select “Developer Components” in Custom Setup. It will install C:\Program Files\MySQL\MySQL Server 5.1\include, lib\debug and lib\opt for you. They are not installed by default.
Uncompress MySQL-python-1.2.3c1.tar.gz into a directory. Open a command window (cmd), change to the directory.
Try to run,
setup.py build
I got this error in setup_windows.py:
in get_config
serverKey = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, options['registry_key'])
WindowsError: [Error 2] The system cannot find the file specified
So I edited site.cfg, changed the MySQL version from 5.0 to 5.1 (since I am using 5.1)
registry_key = SOFTWARE\MySQL AB\MySQL Server 5.1
You can use regedit to check which version you are using. It is specified at: HKEY_LOCAL_MACHINE/SOFTWARE/MySQL AB/MySQL Server 5.1.
Now try to build it again. I got this error:
build\temp.win32-2.6\Release\_mysql.pyd.manifest : general error c1010070: Failed to load and parse the manifest. The system cannot find the file specified.
error: command ‘mt.exe’ failed with exit status 31
To fix this problem, go to C:\Python26\Lib\distutils, edit msvc9compiler.py, search for ‘MANIFESTFILE’, you will find the following line
ld_args.append(’/MANIFESTFILE:’ + temp_manifest)
Then append the following line after the above line,
ld_args.append(’/MANIFEST’)
Then go back to run “setup.py build”, it will succeed. Finally, run
setup.py install
Test it in python
>>> import MySQLdb
>>>
Cannot open libstdc++.so.5 on fedora 11
I just upgraded to fedora 11. When I installed java EE SDK, I got the following error
> ./java_ee_sdk-5_07-linux-nojdk.bin
./java_ee_sdk-5_07-linux-nojdk.bin: error while loading shared libraries: libstdc++.so.5: cannot open shared object file: No such file or directory
The default libstdc++ on fedora is libstdc++.so.6 installed from libstdc++.i586. To solve the problem, install compat-libstdc++-33. For fedora 11, the package can be installed by
> yum install compat-libstdc++-33-3.2.3-66.i586
How to read input files in maven junit
Sometimes we need to put unit test data into plain text files. For example, assume we want to test a parser using a json string as the test data. If we put the json string as a constant string in the java code, we end up with a lot of error-prone escaping characters. In that case, we may want to put the test string into a file as a resource and read the string from the file in junit.
In maven, we need to put the resource file in src/test/resources. Let me create a demo from scratch.
> mvn archetype:create -DgroupId=org.fuyun -DartifactId=junitresdemo > find . . ./junitresdemo ./junitresdemo/pom.xml ./junitresdemo/src ./junitresdemo/src/test ./junitresdemo/src/test/java ./junitresdemo/src/test/java/org ./junitresdemo/src/test/java/org/fuyun ./junitresdemo/src/test/java/org/fuyun/AppTest.java ./junitresdemo/src/main ./junitresdemo/src/main/java ./junitresdemo/src/main/java/org ./junitresdemo/src/main/java/org/fuyun ./junitresdemo/src/main/java/org/fuyun/App.java > cd junitresdemo > mkdir -p src/test/resources > vi src/test/resources/myres.txt > cat src/test/resources/myres.txt test1=testdata
As you can see, I put my test data as a key-value pair in a property file. If your test data contains special characters such as escape char, you’d better handle file reading by yourself instead of using Properties as I am going to show.
Then I modify the automatically generated test code src/test/java/org/fuyun/AppTest.java as follows.
package org.fuyun;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import java.io.InputStream;
import java.util.Properties;
public class AppTest extends TestCase {
public AppTest( String testName ) {
super( testName );
}
public static Test suite() {
return new TestSuite( AppTest.class );
}
public void testApp() throws java.io.IOException {
InputStream in =
getClass().getClassLoader().getResourceAsStream("myres.txt");
Properties p = new Properties();
p.load(in);
String mystr = p.getProperty("test1");
assertEquals("testdata", mystr);
}
}
To read the property file, we need to use getResourceAsStream. Actually this is why I want to write this blog. If you search on web, you may find that people talk about you can load the file using Class.getResourceAsStream(). So, I am supposed to write the line as
InputStream in = getClass().getResourceAsStream("myres.txt");
It can compile. But the test will fail. The InputStream variable in will be null, i.e., it cannot find myres.txt. Why? Why do we have to use the method defined in ClassLoader?
The difference between Class.getResourceAsStream and ClassLoader.getResourceAsStream is that Class.getResourceAsStream attempts to first resolve the file name by appending the package prefix (org/fuyun/) if the file name is not an absolute path, otherwise removes the leading “/” if the path is absolute. Then, it calls the ClassLoader’s getResourceAsStream to load the resolved file name. This is documented here.
For example, if I do the following hack, the test will pass temporarily.
> mv target/test-classes/myres.txt target/test-classes/org/fuyun/. > mvn test
But to really fix it, we should revise the line by adding a leading “/” in the file name as follows.
InputStream in = getClass().getResourceAsStream("/myres.txt");
On the other hand, if you use ClassLoader.getResourceAsStream, the leading “/” will make it unable to find the file.
